ISIL, also known as ISIS, has carried out many similar attacks targeting Iraqi forces in the past months in what many see as an effort to divert attention from the ongoing battle between Iraqi forces and ISIL.

Rutba lies about 390km west of Baghdad. It is the last sizeable town on the way to the border with Jordan.

Just a day earlier, ISIL killed three Iraqi police officers when suicide bombers targeted a police station in Hamam al-Alil, a town located about 30km south of Mosul.

The largest city in northern Iraq, Mosul was captured by ISIL in mid-2014.

Backed by the US-led coalition, Iraqi forces launched an operation, their largest in years, in mid-October last year to retake the city.

They retook the side of the city that lies east of the river Tigris in January and launched a push on remaining ISIL fighters in western Mosul, which is more densely populated and has seen fierce fighting.

Mosul's Old City

On the west bank, Iraqi forces control southern neighbourhoods and are slowly surrounding Mosul's Old City, whose narrow streets are expected to make federal operations very difficult.

Residents who managed to escape from the Old City say that there is almost nothing to eat but flour mixed with water and boiled wheat grain.